You’re in a car traveling at some specified speed limit. You see a car moving at the same speed coming toward you. How fast is the car approaching you, compared with the speed limit?

Solution 7E Suppose that the car I am in is travelling at 50 km/h. The other car coming toward me also has the same speed. That means the car will have a speed of 50 km/h with respect to the ground. But since I am also inside a moving car , hence my observation will measure the other car’s speed as = (50 + 50) km/h = 100 km/h. The car’s approaching speed as compared to my car’s speed limit will be twice the latter.